/*
 * Copyright 2007 Red Hat, Inc.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * on the rights to use, copy, modify, merge, publish, distribute, sub
 * license, and/or sell copies of the Software, and to permit persons to whom
 * the Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.  IN NO EVENT SHALL
 * THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
 * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

/* Author: Soren Sandmann <sandmann@redhat.com> */

#include "edid.h"
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <glib.h>

static int get_bit(int in, int bit)
{
	return (in & (1 << bit)) >> bit;
}

static int get_bits(int in, int begin, int end)
{
	int mask = (1 << (end - begin + 1)) - 1;

	return (in >> begin) & mask;
}

static int decode_header(const uchar* edid)
{
	if (memcmp(edid, "\x00\xff\xff\xff\xff\xff\xff\x00", 8) == 0)
	{
		return TRUE;
	}

	return FALSE;
}

static int decode_vendor_and_product_identification(const uchar* edid, MonitorInfo* info)
{
	int is_model_year;

	/* Manufacturer Code */
	info->manufacturer_code[0] = get_bits(edid[0x08], 2, 6);
	info->manufacturer_code[1] = get_bits(edid[0x08], 0, 1) << 3;
	info->manufacturer_code[1] |= get_bits(edid[0x09], 5, 7);
	info->manufacturer_code[2] = get_bits(edid[0x09], 0, 4);
	info->manufacturer_code[3] = '\0';

	info->manufacturer_code[0] += 'A' - 1;
	info->manufacturer_code[1] += 'A' - 1;
	info->manufacturer_code[2] += 'A' - 1;

	/* Product Code */
	info->product_code = edid[0x0b] << 8 | edid[0x0a];

	/* Serial Number */
	info->serial_number = edid[0x0c] | edid[0x0d] << 8 | edid[0x0e] << 16 | edid[0x0f] << 24;

	/* Week and Year */
	is_model_year = FALSE;

	switch (edid[0x10])
	{
		case 0x00:
			info->production_week = -1;
			break;

		case 0xff:
			info->production_week = -1;
			is_model_year = TRUE;
			break;

		default:
			info->production_week = edid[0x10];
			break;
	}

	if (is_model_year)
	{
		info->production_year = -1;
		info->model_year = 1990 + edid[0x11];
	}
	else
	{
		info->production_year = 1990 + edid[0x11];
		info->model_year = -1;
	}

	return TRUE;
}

static int decode_edid_version(const uchar* edid, MonitorInfo* info)
{
	info->major_version = edid[0x12];
	info->minor_version = edid[0x13];

	return TRUE;
}

static int decode_display_parameters(const uchar* edid, MonitorInfo* info)
{
	/* Digital vs Analog */
	info->is_digital = get_bit(edid[0x14], 7);

	if (info->is_digital)
	{
		int bits;

		static const int bit_depth[8] = {
			-1, 6, 8, 10, 12, 14, 16, -1
		};

		static const Interface interfaces[6] = {
			UNDEFINED, DVI, HDMI_A, HDMI_B, MDDI, DISPLAY_PORT
		};

		bits = get_bits(edid[0x14], 4, 6);
		info->connector.digital.bits_per_primary = bit_depth[bits];

		bits = get_bits(edid[0x14], 0, 3);

		if (bits <= 5)
		{
			info->connector.digital.interface = interfaces[bits];
		}
		else
		{
			info->connector.digital.interface = UNDEFINED;
		}
	}
	else
	{
		int bits = get_bits (edid[0x14], 5, 6);

		static const double levels[][3] = {
			{ 0.7,   0.3,	1.0 },
			{ 0.714, 0.286,  1.0 },
			{ 1.0,   0.4,	1.4 },
			{ 0.7,   0.0,	0.7 },
		};

		info->connector.analog.video_signal_level = levels[bits][0];
		info->connector.analog.sync_signal_level = levels[bits][1];
		info->connector.analog.total_signal_level = levels[bits][2];

		info->connector.analog.blank_to_black = get_bit (edid[0x14], 4);

		info->connector.analog.separate_hv_sync = get_bit (edid[0x14], 3);
		info->connector.analog.composite_sync_on_h = get_bit (edid[0x14], 2);
		info->connector.analog.composite_sync_on_green = get_bit (edid[0x14], 1);

		info->connector.analog.serration_on_vsync = get_bit (edid[0x14], 0);
	}

	/* Screen Size / Aspect Ratio */
	if (edid[0x15] == 0 && edid[0x16] == 0)
	{
		info->width_mm = -1;
		info->height_mm = -1;
		info->aspect_ratio = -1.0;
	}
	else if (edid[0x16] == 0)
	{
		info->width_mm = -1;
		info->height_mm = -1;
		info->aspect_ratio = 100.0 / (edid[0x15] + 99);
	}
	else if (edid[0x15] == 0)
	{
		info->width_mm = -1;
		info->height_mm = -1;
		info->aspect_ratio = 100.0 / (edid[0x16] + 99);
		info->aspect_ratio = 1/info->aspect_ratio; /* portrait */
	}
	else
	{
		info->width_mm = 10 * edid[0x15];
		info->height_mm = 10 * edid[0x16];
	}

	/* Gamma */
	if (edid[0x17] == 0xFF)
		info->gamma = -1.0;
	else
		info->gamma = (edid[0x17] + 100.0) / 100.0;

	/* Features */
	info->standby = get_bit(edid[0x18], 7);
	info->suspend = get_bit(edid[0x18], 6);
	info->active_off = get_bit(edid[0x18], 5);

	if (info->is_digital)
	{
		info->connector.digital.rgb444 = TRUE;

		if (get_bit(edid[0x18], 3))
			info->connector.digital.ycrcb444 = 1;
		if (get_bit(edid[0x18], 4))
			info->connector.digital.ycrcb422 = 1;
	}
	else
	{
		int bits = get_bits(edid[0x18], 3, 4);

		ColorType color_type[4] = {
			MONOCHROME, RGB, OTHER_COLOR, UNDEFINED_COLOR
		};

		info->connector.analog.color_type = color_type[bits];
	}

	info->srgb_is_standard = get_bit(edid[0x18], 2);

	/* In 1.3 this is called "has preferred timing" */
	info->preferred_timing_includes_native = get_bit(edid[0x18], 1);

	/* FIXME: In 1.3 this indicates whether the monitor accepts GTF */
	info->continuous_frequency = get_bit(edid[0x18], 0);

	return TRUE;
}

static double decode_fraction(int high, int low)
{
	double result = 0.0;
	int i;

	high = (high << 2) | low;

	for (i = 0; i < 10; ++i)
	{
		result += get_bit (high, i) * pow (2, i - 10);
	}

	return result;
}

static int decode_color_characteristics(const uchar* edid, MonitorInfo* info)
{
	info->red_x = decode_fraction(edid[0x1b], get_bits(edid[0x19], 6, 7));
	info->red_y = decode_fraction(edid[0x1c], get_bits(edid[0x19], 5, 4));
	info->green_x = decode_fraction(edid[0x1d], get_bits(edid[0x19], 2, 3));
	info->green_y = decode_fraction(edid[0x1e], get_bits(edid[0x19], 0, 1));
	info->blue_x = decode_fraction(edid[0x1f], get_bits(edid[0x1a], 6, 7));
	info->blue_y = decode_fraction(edid[0x20], get_bits(edid[0x1a], 4, 5));
	info->white_x = decode_fraction(edid[0x21], get_bits(edid[0x1a], 2, 3));
	info->white_y = decode_fraction(edid[0x22], get_bits(edid[0x1a], 0, 1));

	return TRUE;
}

static int decode_established_timings(const uchar* edid, MonitorInfo* info)
{
	static const Timing established[][8] = {
		{
			{800, 600, 60},
			{800, 600, 56},
			{640, 480, 75},
			{640, 480, 72},
			{640, 480, 67},
			{640, 480, 60},
			{720, 400, 88},
			{720, 400, 70}
		},
		{
			{1280, 1024, 75},
			{1024, 768, 75},
			{1024, 768, 70},
			{1024, 768, 60},
			{1024, 768, 87},
			{832, 624, 75},
			{800, 600, 75},
			{800, 600, 72}
		},
		{
			{0, 0, 0},
			{0, 0, 0},
			{0, 0, 0},
			{0, 0, 0},
			{0, 0, 0},
			{0, 0, 0},
			{0, 0, 0},
			{1152, 870, 75}
		},
	};

	int i, j, idx;

	idx = 0;

	for (i = 0; i < 3; ++i)
	{
		for (j = 0; j < 8; ++j)
		{
			int byte = edid[0x23 + i];

			if (get_bit (byte, j) && established[i][j].frequency != 0)
			{
				info->established[idx++] = established[i][j];
			}
		}
	}

	return TRUE;
}

static int decode_standard_timings(const uchar* edid, MonitorInfo* info)
{
	int i;

	for (i = 0; i < 8; i++)
	{
		int first = edid[0x26 + 2 * i];
		int second = edid[0x27 + 2 * i];

		if (first != 0x01 && second != 0x01)
		{
			int w = 8 * (first + 31);
			int h = 0;

			switch (get_bits(second, 6, 7))
			{
				case 0x00:
					h = (w / 16) * 10;
					break;
				case 0x01:
					h = (w / 4) * 3;
					break;
				case 0x02:
					h = (w / 5) * 4;
					break;
				case 0x03:
					h = (w / 16) * 9;
					break;
			}

			info->standard[i].width = w;
			info->standard[i].height = h;
			info->standard[i].frequency = get_bits(second, 0, 5) + 60;
		}
	}

	return TRUE;
}

static void decode_lf_string(const uchar* s, int n_chars, char* result)
{
	int i;

	for (i = 0; i < n_chars; ++i)
	{
		if (s[i] == 0x0a)
		{
			*result++ = '\0';
			break;
		}
		else if (s[i] == 0x00)
		{
			/* Convert embedded 0's to spaces */
			*result++ = ' ';
		}
		else
		{
			*result++ = s[i];
		}
	}
}

static void decode_display_descriptor(const uchar* desc, MonitorInfo* info)
{
	switch (desc[0x03])
	{
		case 0xFC:
			decode_lf_string (desc + 5, 13, info->dsc_product_name);
			break;
		case 0xFF:
			decode_lf_string (desc + 5, 13, info->dsc_serial_number);
			break;
		case 0xFE:
			decode_lf_string (desc + 5, 13, info->dsc_string);
			break;
		case 0xFD:
			/* Range Limits */
			break;
		case 0xFB:
			/* Color Point */
			break;
		case 0xFA:
			/* Timing Identifications */
			break;
		case 0xF9:
			/* Color Management */
			break;
		case 0xF8:
			/* Timing Codes */
			break;
		case 0xF7:
			/* Established Timings */
			break;
		case 0x10:
			break;
	}
}

static void decode_detailed_timing(const uchar* timing, DetailedTiming* detailed)
{
	int bits;

	StereoType stereo[] = {
		NO_STEREO, NO_STEREO, FIELD_RIGHT, FIELD_LEFT,
		TWO_WAY_RIGHT_ON_EVEN, TWO_WAY_LEFT_ON_EVEN,
		FOUR_WAY_INTERLEAVED, SIDE_BY_SIDE
	};

	detailed->pixel_clock = (timing[0x00] | timing[0x01] << 8) * 10000;
	detailed->h_addr = timing[0x02] | ((timing[0x04] & 0xf0) << 4);
	detailed->h_blank = timing[0x03] | ((timing[0x04] & 0x0f) << 8);
	detailed->v_addr = timing[0x05] | ((timing[0x07] & 0xf0) << 4);
	detailed->v_blank = timing[0x06] | ((timing[0x07] & 0x0f) << 8);
	detailed->h_front_porch = timing[0x08] | get_bits(timing[0x0b], 6, 7) << 8;
	detailed->h_sync = timing[0x09] | get_bits(timing[0x0b], 4, 5) << 8;
	detailed->v_front_porch =
	get_bits (timing[0x0a], 4, 7) | get_bits(timing[0x0b], 2, 3) << 4;
	detailed->v_sync =
	get_bits (timing[0x0a], 0, 3) | get_bits(timing[0x0b], 0, 1) << 4;
	detailed->width_mm =  timing[0x0c] | get_bits(timing[0x0e], 4, 7) << 8;
	detailed->height_mm = timing[0x0d] | get_bits(timing[0x0e], 0, 3) << 8;
	detailed->right_border = timing[0x0f];
	detailed->top_border = timing[0x10];

	detailed->interlaced = get_bit(timing[0x11], 7);

	/* Stereo */
	bits = get_bits (timing[0x11], 5, 6) << 1 | get_bit(timing[0x11], 0);
	detailed->stereo = stereo[bits];

	/* Sync */
	bits = timing[0x11];

	detailed->digital_sync = get_bit(bits, 4);

	if (detailed->digital_sync)
	{
		detailed->connector.digital.composite = !get_bit(bits, 3);

		if (detailed->connector.digital.composite)
		{
			detailed->connector.digital.serrations = get_bit(bits, 2);
			detailed->connector.digital.negative_vsync = FALSE;
		}
		else
		{
			detailed->connector.digital.serrations = FALSE;
			detailed->connector.digital.negative_vsync = !get_bit(bits, 2);
		}

		detailed->connector.digital.negative_hsync = !get_bit(bits, 0);
	}
	else
	{
		detailed->connector.analog.bipolar = get_bit(bits, 3);
		detailed->connector.analog.serrations = get_bit(bits, 2);
		detailed->connector.analog.sync_on_green = !get_bit(bits, 1);
	}
}

static int decode_descriptors(const uchar* edid, MonitorInfo* info)
{
	int i;
	int timing_idx;

	timing_idx = 0;

	for (i = 0; i < 4; ++i)
	{
		int index = 0x36 + i * 18;

		if (edid[index + 0] == 0x00 && edid[index + 1] == 0x00)
		{
			decode_display_descriptor(edid + index, info);
		}
		else
		{
			decode_detailed_timing(edid + index, &(info->detailed_timings[timing_idx++]));
		}
	}

	info->n_detailed_timings = timing_idx;

	return TRUE;
}

static void decode_check_sum(const uchar* edid, MonitorInfo* info)
{
	int i;
	uchar check = 0;

	for (i = 0; i < 128; ++i)
	{
		check += edid[i];
	}

	info->checksum = check;
}

MonitorInfo* decode_edid(const uchar* edid)
{
	MonitorInfo* info = g_new0(MonitorInfo, 1);

	decode_check_sum(edid, info);

	if (decode_header(edid) && decode_vendor_and_product_identification(edid, info) && decode_edid_version(edid, info) && decode_display_parameters(edid, info) && decode_color_characteristics(edid, info) && decode_established_timings(edid, info) && decode_standard_timings(edid, info) && decode_descriptors(edid, info))
	{
		return info;
	}
	else
	{
		g_free(info);
		return NULL;
	}
}
